Penny has no interest
in subatomic PARTICLE research.
The Big Bang Theory Season 3, Episode 15
Here, we have a highly gifted researcher
in the field of PARTICLE physics...
The Big Bang Theory Season 3, Episode 15
A sigma PARTICLE.
The Big Bang Theory Season 1, Episode 13
...of a subatomic PARTICLE
called the Higgs boson.
The Big Bang Theory Season 6, Episode 3
inventing a new
dark matter PARTICLE
The Big Bang Theory Season 11, Episode 13